SUS316L Stainless Steel

SUS316L is a low-carbon variant of SUS316 (C <=0.03%), combining molybdenum's corrosion resistance with low carbon's weldability. It eliminates intergranular corrosion after welding, making it ideal for large welded structures in harsh environments.

: C <=0.03, Si <=1.00, Mn <=2.00, P <=0.045, S <=0.030, Cr=16.00-18.00, Ni=10.00-14.00, Mo=2.00-3.00, Fe=Balance

: Tensile Strength >=485MPa, Yield Strength >=170MPa, Elongation >=40%, Hardness (HB) <=217

: Excellent intergranular corrosion resistance after welding; superior chloride pitting resistance; good low-temperature toughness; suitable for heavy welding.

: ASTM A240 316L, EN 1.4404, UNS S31603

: Offshore oil platforms, large chemical storage tanks, seawater pipelines, medical implants, semiconductor equipment, food processing in coastal areas.

1. Q: What makes SUS316L suitable for medical implants? A: It meets biocompatibility standards. Low carbon (<=0.03%) avoids toxic ion release, and Mo enhances corrosion resistance in body fluids (rich in chloride). It's non-magnetic, compatible with MRI scans. Its ductility allows shaping into implants (screws, hip joints), and it bonds well with human tissue. Unlike SUS316, its weld corrosion resistance ensures implant integrity if welded, reducing rejection risks.

2. Q: How does SUS316L perform in low-temperature environments? A: It's excellent for cryogenics, with usable temp down to -196℃. Low carbon improves toughness, preventing brittle fracture at low temps. The stable austenitic structure retains ductility, making it suitable for liquid nitrogen storage tanks, LNG pipelines, and aerospace cryogenic components. SUS316 (higher C) is less tough at low temps, so SUS316L is preferred for cold-region applications.

3. Q: Can SUS316L be used in high-concentration acid environments? A: It resists most dilute acids, but high-concentration (>=90% sulfuric acid) or oxidizing acids (nitric acid) may corrode it. For 5-30% sulfuric acid at room temp, it works well; above 60℃, use Hastelloy. It resists dilute hydrochloric acid but not concentrated. For aggressive acids, test in actual conditions first. Its corrosion resistance is better than SUS304L but inferior to specialty alloys like titanium.

4. Q: What's the difference between SUS316 and SUS316L in welding? A: SUS316L needs no post-weld heat treatment due to low carbon, while SUS316 may require annealing to prevent intergranular corrosion. Both use ER316L filler metal, but SUS316L's weld zone has no chromium carbide precipitation. For large structures (offshore platforms) with multiple welds, SUS316L simplifies fabrication and reduces costs, ensuring long-term corrosion resistance.

5. Q: How to maintain SUS316L equipment in coastal areas? A: Coastal salt spray is the main threat. Clean surfaces monthly with fresh water to remove salt deposits. For welded areas, apply anti-corrosion coating if needed. Avoid scratches-repair them promptly with polishing. Use passivation treatment (nitric acid solution) annually to restore the oxide film. Regular inspection for pitting, especially in crevices (flange joints), ensures early maintenance and extends service life.